1. Field of the Invention
The present invention relates to methods to form a device that includes flexible circuit board elements skirting the optical zone of a powered ophthalmic lens or similar device. More specifically, the flexible circuit board may be deformed or bent in order to attach to three-dimensionally shaped or flexible active components.
2. Discussion of the Related Art
As electronic devices continue to be miniaturized, it is becoming increasingly more likely to create wearable or embeddable microelectronic devices for a variety of uses. Such uses include monitoring aspects of body chemistry, administering controlled dosages of medications or therapeutic agents via various mechanisms, including automatically, in response to measurements, or in response to external control signals, and augmenting the performance of organs or tissues. Examples of such devices include glucose infusion pumps, pacemakers, defibrillators, ventricular assist devices and neurostimulators. A new, particularly useful field of application is in ophthalmic wearable lenses and contact lenses. For example, a wearable lens may incorporate a lens assembly having an electronically adjustable focus to correct refractive errors and/or augment or enhance performance of the eye. In another example, either with or without adjustable focus, a wearable contact lens may incorporate electronic sensors to detect concentrations of particular chemicals in the precorneal (tear) film. The use of embedded electronics in a lens introduces a potential requirement for communication with the electronics, for a method of powering and/or re-energizing the electronics, for interconnecting the electronics, for internal and external sensing and/or monitoring, and for control of the electronics and the overall function of the lens.
The human eye has the ability to discern millions of colors, adjust easily to shifting light conditions, and transmit signals or information to the brain at a rate exceeding that of a high-speed internet connection. Lenses, such as contact lenses and intraocular lenses, currently are utilized to correct vision defects such as myopia (nearsightedness), hyperopia (farsightedness), presbyopia, and astigmatism. However, properly designed lenses incorporating additional components may be utilized to enhance vision as well as to correct vision defects.
Contact lenses may be utilized to correct myopia, hyperopia, astigmatism as well as other visual acuity defects. Contact lenses may also be utilized to enhance the natural appearance of the wearer's eyes. Contact lenses or “contacts” are simply lenses placed on the anterior surface of the eye. Contact lenses are considered medical devices and may be worn to correct vision and/or cosmetic or other therapeutic reasons. Contact lenses have been utilized commercially to improve vision since the 1950s. Early contact lenses were made or fabricated from hard materials, were relatively expensive and fragile. In addition, these early contact lenses were fabricated from materials that did not allow sufficient oxygen transmission through the contact lens to the conjunctiva and cornea which potentially could cause a number of adverse clinical effects. Although these contact lenses are still utilized, they are not suitable for all patients due to their poor initial comfort. Later developments in the field gave rise to soft contact lenses, based upon hydrogels, which are extremely popular and widely utilized today. Specifically, silicone hydrogel contact lenses that are available today combine the benefit of silicone, which has extremely high oxygen permeability, with the proven comfort and clinical performance of hydrogels. Essentially, these silicon hydrogel based contact lens have higher oxygen permeability and are generally more comfortable to wear than the contact lenses made of the earlier hard materials.
Conventional contact lenses are polymeric structures with specific shapes to correct various vision problems as briefly set forth above. To achieve enhanced functionality various electronic circuits and components have to be integrated into these polymeric structures. For example, control circuits, microprocessors, communication devices, power supplies, sensors, actuators, light-emitting diodes, and miniature antennas may be integrated into contact lenses via custom-built optoelectronic components to not only correct vision, but to enhance vision as well as provide additional functionality as is explained herein. Electronic and/or powered contact lenses may be designed to provide enhanced vision via zoom-in and zoom-out capabilities, or just simply modifying the refractive capabilities of the lens. Electronic and/or powered contact lenses may be designed to enhance color and resolution, to display textural information, to translate speech into captions in real time, to offer visual cues from a navigation system, and to provide image processing and internet access. The lenses may be designed to allow the wearer to see in low-light conditions. The properly designed electronics and/or arrangement of electronics on lenses may allow for projecting an image onto the retina, for example, without a variable-focus optic lens, provide novelty image displays and even provide wake up alerts. Alternately, or in addition to any of these function or similar functions, the contact lens may incorporate components for the noninvasive monitoring of the wearer's biomarkers and health indicators. For example, sensors built into the lenses may allow a diabetic patient to keep tabs on blood sugar levels by analyzing components of the tear film without the need for drawing blood. In addition, an appropriately configured lens may incorporate sensors for monitoring cholesterol, sodium, and potassium levels, as well as other biological markers. This, coupled with a wireless data transmitter, could allow a physician to have almost immediate access to a patient's blood chemistry without the need for the patient to waste time getting to a laboratory and having blood drawn. In addition, sensors build into the lenses may be utilized to detect light incident on the eye to compensate for ambient light conditions or for use in determining blink patterns.
The proper combination of devices could yield potentially unlimited functionality; however, there are number of difficulties associated with the incorporation of extra components on a piece of optical-grade polymer. In general, it may be difficult to manufacture such components directly on the lens for a number of reasons, as well as mounting and interconnecting planar devices on a non-planar surface. It may also be difficult to manufacture to scale. The components to be placed on or in the lens need to be miniaturized and integrated onto just 1.5 square centimeters (assuming a lens with a 7 mm radius) of the transparent polymer while protecting components from the liquid environment on the eye. It may also be difficult to make a contact lens comfortable and safe for the wearer with the added thickness of additional components.
More specifically, the 1.5 square centimeters of transparent polymer represents the entire area of the contact lens. In certain exemplary embodiments, it is preferable that the electronics be in the periphery of the lens and out of the optic zone. Alternate exemplary embodiments are also possible utilizing thin-film materials or transparent silicon. In the above example, if the center eight (8) mm diameter portion (4 mm radius) is reserved for the optic zone, then at most one (1) square centimeter is left for the electronics. Future designs may offer even less area for electronics, for example, there may be designs with annular rings of about 0.017 square centimeters (17 square millimeters) not including the variable-focus optic. In other words, what is needed in the present invention is a design and configuration that allows for incorporation of all the components necessary to exploit the aforementioned unlimited functionality.
Given the area and volume constraint of an ophthalmic device such as a contact lens, and the environment in which it is to be utilized, the physical realization of the device must overcome a number of problems, including mounting and interconnecting a number of electronic components on a non-planar surface, the bulk of which comprises optical grade plastic. Accordingly, there exists a need for providing a mechanically and electrically robust electronic contact lens.
The topology and size of the space defined by the lens structure creates a novel and challenging environment for the investigation of virtually unlimited functionality of an ophthalmic device. In many embodiments, it is important to provide reliable, compact, and cost effective means to incorporate components within an ophthalmic device. In some embodiments, it may be advantageous to include thin and flexible surfaces upon which electrical components may be mounted. As a result, novel methods and form factor solutions that may allow for modulation of flexibility of some components are desired both for improvements in the production of ophthalmic devices and for the general advancement of incorporating electronic components on non-flat substrates. It is important to note these improvements may find use in non-ophthalmic applications as well. It is also desirable that methods be generated to address ophthalmic and non-ophthalmic requirements as they relate to electronic components on three-dimensional substrates.